Periprosthetic osteolysis depends on the biological activity of wear particles, but there is little known about the distribution of polyethylene wear particles (PE) in the surrounding joint tissue. The purpose of this study was to examine the localisation of wear particles of six different PEs, including four crosslinked polyethylenes (XPE), as well as their biological activity in the murine knee. Material and Methods. Wear particles of 4 XPE- and 2 UHMWPE-inserts were isolated (knee joint simulator). For all groups the particles were similar in size and shape (mean diameter 0.3–05μm; 20nm-nucleopore-filter; ISO; n = 100.000).56 female Balb/c mice were randomly assigned to six treatment groups and one control group: control (PBS), XPE1 (3×30 kGy Gamma, annealed/sequential irradiated), XPE2 (95 kGy E-beam, remelted), XPE3 (65 kGy E-beam, remelted), XPE 4 (50 kGy Gamma, remelted), UHMWPE 1, UHMWPE 2. 50 μl of each particle suspension [(0.1% vol/vol (particle volume/PBS volume) after removal of endotoxin] were injected into the left knee joint. After 1 week the mice were killed and a histological and immunhistochemical analysis of the knee joints was done (IL-1, TNF-, ICAM-1). For the immunhistochemistry the articular cartilage, the bone marrow and the synovial membrane were evaluated semiquantitatively (Kruskal-Wallis test; all pairwise multiple comparison procedure; Bonferoni correction; significance level: p<0.05). Results. All groups showed a thickened synovial layer with an increased cellular infiltration. The particles of XPE 1 and 2 were localised in the bone marrow as well as in the joint space. In contrast, the particles of XPE 3 and 4 were distributed in the synovial layer and in the bone marrow as well, but not in the joint space. The UHMWPE1 particles were mainly located in the bone marrow and joint space while the UHMWPE2 particles were mainly found in the bone marrow and the synovial layer. For all PE groups there was a higher cytokine expression compaired to control (p<0.0024) without any differences between the groups (bone marrow/synovial layer). The chondrocytes in the groups with XPE 1- and XPE 2-particles expressed more TNF- than in the control group and the other treatment groups (p = 0.000). Conclusion. XPEs lead to a similar inflammatory reaction in vivo compared to conventional polyethylenes. The high TNF- expression in the articular cartilage (groups XPE 1 and 2) might be explained by the localisation of the wear particles in the joint space in direct contact with the chondrocytes. Long-term studies are necessary to analyse the effects of different wear particle distributions in the joint surrounding tissue after knee and hip replacement. Furthermore it has to be investigated, whether their distribution in the joint space or their transport into the bone marrow is responsible for the level of the chronic inflammatory reaction

Introduction. Anatomical reduction of articular fragments in tibial plateau fractures often leads to a void and there is a need to fill dead space and support the articular fragment. MIIG X3 is marketed as high strength injectable graft, which resorbs and remodels fast. Efficacy and complications related to the use of this bone graft substitute were evaluated in this study. Methods. Between January 2012 and December 2016 we injected calcium sulphate (MIIGX3) in 50 out of 126 consecutive complete articular (AO type C3) tibial plateau fractures that were stabilised with Ilizarov ring fixator. Postoperative CT scans after weight bearing and sequential radiographs were evaluated for union, graft resorption and subsidence. IOWA functional outcome score and complications were recorded. Results. The median age was 52 (Range 17–87) years. Post-operative CT scans showed leak of the graft into the joint in 11 patients and around the proximal tibiofibular joint in 2 patients but this disappeared spontaneously in all patients. Average time for graft resorption was 3.1 months. Union occurred in all patients. Minor subsidence was noted in almost half of these patients. There was no significant difference in IOWA knee score between those with or without MIIGX3 at final follow up. (p value > 0.05). Conclusion. MIIGX3 is effective as a void filler providing articular support, eradicating dead space and potentially reducing the risk of infection. Leak in the joint or soft tissue resorbed spontaneously in all cases without complications or need for surgical removal. Its use may also be associated with lack of significant late subsidence

Aims

We aimed to identify the pattern of nerve injury associated with paediatric supracondylar fractures of the humerus.

Objectives

The PROximal Fracture of the Humerus: Evaluation by Randomisation (PROFHER) trial has recently demonstrated that surgery is non-superior to non-operative treatment in the management of displaced proximal humeral fractures. The objective of this study was to assess current surgical practice in the context of the PROFHER trial in terms of patient demographics, injury characteristics and the nature of the surgical treatment.